U.S. Pat. No. 3,965,143 generally describes compounds of the formula ##STR3## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.6 and R.sub.7 can be hydrogen or a lower alkyl radical, R.sub.5 can be hydrogen or a lower alkanoyl, tetrahydrofuranyl, tetrahydropyran-2-yl, tri(-lower alkyl)silyl or lower alkyl radical, X is a carbonyl, hydroxymethylene or (lower alkanoyl)oxymethylene radical, V is a methylene, hydroxymethylene, (lower alkanoyl)oxymethylene, tetrahydrofuranyloxymethylene, tetrahydropyran-2-yloxymethylene or tri-(lower alkyl)silyloxymethylene radical, Y is an ethylene, cis vinylene or trans-vinylene group, Z is an ethylene, cis vinylene, trans-vinylene or ethynylene radical, the wavy lines denote the alternative .alpha. and .beta. stereochemical configurations, the dotted line indicates an optional double bond, m is an integer greater than 2 and less than 5 and R.sub.8 is an alkyl group containing 3-5 carbon atoms or cycloalkyl group containing 5-7 carbon atoms,
and specifically describes methyl 7-[3(R)-hydroxy-2.beta.-(4(RS)-4-cyclohexylmethyl-4-hydroxy-4-methyl-trans -1-butenyl)-5-oxocyclopentane]-1.alpha.-heptanoate, a compound of the formula. ##STR4## British Pat. No. 1,492,426 describes compounds of the structural formula. ##STR5## wherein R.sub.1, R.sub.2, and R.sub.3 are hydrogen or an alkyl radical containing from 1 to 7 carbon atoms; R.sub.4 is an alkyl radical containing from 1 to 7 carbon atoms; R.sub.5 is hydrogen, an alkyl radical containing from 1 to 7 carbon atoms or an alkanoyl radical containing from 1 to 7 carbon atoms; R.sub.6 is an alkyl radical containing from 2 to 4 carbon atoms or a cycloalkyl radical containing from 5 to 7 carbon atoms; X is carbonyl or hydroxymethylene; V is methylene, hydroxymethylene or alkanoyloxymethylene wherein the alkanoyl radical contains from 1 to 7 carbon atoms; or when X is carbonyl; V may also be a radical of the formula ##STR6## in which the bond represented by the dotted line in the general formula is present; Y is ethylene or vinylene; Y' is vinylene, ethynylene or the group ##STR7## wherein n is 0 to 1 and R.sub.7 and R.sub.8 are hydrogen or an alkyl radical containing from 1 to 7 carbon atoms; Z is ethylene, vinylene or ethynylene; and the wavy lines represent the alternative .alpha. or .beta. stereochemical configuration or the epimeric mixture:
The alkyl radicals represented in the foregoing structural formula are illustrated by methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and branched-chain isomers thereof.
The alkanoyl radicals designated in the foregoing formula are exemplified by formyl, acetyl, propionyl, butyryl, valeryl, hexanoyl, heptanoyl, and the corresponding branched-chain isomers.
The cycloalkyl groups designated in the foregoing formula are exemplified by cyclopentyl and cyclohexyl.
Compounds of this invention differ structurally in that they have a cis vinylene radical at the 4-5 postions.